This disclosure deals with the field of water treatment, especially the technical field of water disinfection utilizing a chlorine species. Chlorine species are globally the most commonly used disinfectants for water.
An important drawback for chlorine based disinfection however is the production of so called “disinfection by-products” (DBPs). These by-products may have negative effect to health of organisms consuming such disinfected water containing these by-products.
Chlorine DBPs can be divided into organic and inorganic DBPs. For both groups strict limits have been set for disinfected waters by the respective institutions. For inorganic DBPs the most important species are chlorite (ClO2−) and chlorate ClO3−.
Chlorite has been already restricted in many countries due to its negative health effects, especially for humans. For chlorate less knowledge exists on the impact on human health but more and more studies give reason for further limitations for concentrations of chlorate in disinfected water, especially drinking water.
The introduction of threshold values for concentrations of chlorate in water sources is therefore expected in nearer future, e.g. for swimming pools. For other water sources, especially drinking water, similar steps are expected in the future. Already today the World Health Organization (WHO) recommends an upper threshold value for chlorate concentration of 1 milligram per liter for drinking water.
To restrict the concentration of chlorate in aqueous solutions to certain maximum level, it is necessary to be able to measure the concentrations of chlorate-ions in aqueous solutions.
Today such measurements can be provided by ion chromatography. These methods are able to do an offline analysis with specific samples of the aqueous solution. These kinds of measurements generate significant efforts, are expensive due to involvement of laboratories and normally may not be executed in the facility the water is treated, especially are not able to be executed online as part of the water treatment process.